I'm looking for a word that means an emphatic, definitely correct, powerful assertion, kind of like "undeniable" except that doesn't capture the action aspect of making a statement. (A thesaurus didn't help).
Things that almost work and why:
Proclamation - it gets the loud announcement aspect but misses the factual and undeniable aspects. One can make an incorrect proclamation.
Axiom - An axiom is certainly accurate and provable but axiom gives no indication of the method of delivery.
Apodictic - it gets the clearly established and beyond dispute but again misses the emphatic delivery aspect
to describe the act of yelling "the building is on fire" to twenty people who are standing nearby and somehow haven't noticed fifteen-meter flames coming out the windows. "Bob was kind enough to make the _____ that the building was on fire."
When someone has a banana in their ear and they can't hear you say "you have a banana in your ear!" you've stated a _____.
In response to close vote as discussed in comments below: "..undeniability (stating the obvious) is only a part of the idea to be conveyed. In my example of the fire, no one knew the building was burning so though it was obvious, no one noticed. The question you link to [as duplicate] requests something that describes telling a fact everyone already knows.."